I just read your private message. I wanted to post on here so that anyone else looking for guidance can read also.
Most of this is my opinion and relates to how I think a mustang should perform. I am a restod guy. I had an original mustang. It was my first mustang. Their performance stock is less than stellar. However, they can be a blast to drive with some modern updates.
My coupe build was completed about a year ago and goes like this:
I think all good builds start with the wheels you want and that can fit the car. Tire diameter must fit the car as well. Then the rear gears and transmission are selected for driving purposes. I like the T5z. The install procedure is well documented on the internet and it makes the car fun to drive. Gear according to your pleasure, with a T5 3.25 to 3.89's are the best choices. I would say the 3.25 is better for distance and daily driving while the higher numbers are more performance oriented. Engine according to use. Otherwise an AOD (automatic overdrive) from a later fox body would be the next choice for a restomod type build. AOD's are 4 speeds where the old C4 tranny's were only 3.
I wanted a 5 spoke wheel that wasn't like eveybody elses. AFter I chose the wheel, I realized drum brakes would detract from the look. Plus, it gave me an excuse to install 4wdb (wheel disc brakes). I used the dodgestang chart to help me find a wheel and tire size that would fit my car.
Brakes (discs are only needed up front for the most part)
Wilwood discs at all four corners, they came with a parts car
wilwood master cylinder, their tech can help you with the correct bore size
new braided lines up front, I made the rears from stocked lengths at a local parts store
mustang chassis to rear end brake line
Please note this brake kit pushed the hub out almost a half inch which can affect wheel selection
Please note that disc brakes will require new wheel studs, always read the instructions thoroughly before purchasing a brake kit
I was on a limited budget for this, my first, build. I went with a grab a track "620" front coil springs (they lower 1"), 1" sway bar, roller perches, upper control arm (UCA) 1" shelby drop and home made solid mounted adjustable strut rods. I made the roller perches from a kit sold by dazecars.net. There is some good reading there on suspension improvements. I used stock upper and lower control arms. KYB GR2 shocks
custom 5 leafs dropped about an inch from a local shop, it was a hassle. I wish I ordered a set from a mustang supplier.
Stock with some modifications
I relocated the battery and starter solenoid to the trunk. There are several writeups on the internet. The headlights are on relays. Relays are electric switches. These old cars don't always put out 12 volts at the headlights. This is due to inadequate and aged wiring and switches. When you wire the headlights with relays, you use the existing switch as a low current lead for a higher amperage electric switch (relay). there are write ups about this on the net too. I used a late model fox alternator and integral voltage regulator. The wiring had to be altered to eliminate the old reg and mate with the new plug on the fox alternator. The advantage is a better regulator and more amperage, if you use the correct alternator.
Stock, I like the classic look.
Because I am sort of a cheap ***, I found a used 302 ho from a fox. There was a guy here in Phoenix who buys them cheap and parts them out. I asked him to call me before he disassembles his next victim. I heard the engine run and saw the oil pressure. The coolant looked good and the oil wasn't bad. It was cheap, like, $300 for a longblock with alt, ps pump, pullioes,timing chain cover, and brackets for ps and alt. The next step was to drill the timing chain cover for a dipstick and replace the front and rear main seals. Next, new front sump oil pan, valve covers and gaskets. Block off the egr holes in the head and the old dipstick hole in the block. After that I needed a flywheel, fan, motor mounts, distributor, intake, carb and trick flow fox bady A/C delete to complete the serpentine belt routing. the PS wasn't used. I also needed a radiator for the new waterpump hose routing.
This will depend on budget but I think a new T5z is the best way to go. You may find the bellhousing and fork used to save some money. Buy the clutch, pressure plate, throwout bearing and pilot bearing new. They come in kits.
Make sure your bell housing works with the T5z before you buy it. 94-95 mustangs use different parts than 87ish-93. You will need a tranny crossmember. Many places sell them. I made mine.
A vintage mustang C4 automatic driveshaft may fit right into a T5 or T5z. Some have had no problems, others say it fits right in. I found a local vintage mustang shop with a gaggle of them used. I measured what I needed and brought from them. New ujoints are a good idea. Make sure that the rear matches the differential.
clutch pedals and cable
mustang steve has info on this and sells kits.
I used headman shorty heads and had to modify the driver side to clear the clutch cable mounting ear on the bell housing. There are headers that clear without modifications. Do some research. 2.25" should be big enough unless you are getting close to 300hp and you should go to 2.5".
I used the Unisteer manual rack and pinion. It replaced the engine crossmember and tucks neatly out of the way.
Stock stuff from catalogs
Exterior bolt ons
Stock stuff from catalogs
Things to look out for:
wheel/tire fitment to car body
wheel fitment to brakes
header fitment to steering
header fitment to bellhousing
oil pan fitment to crossmember
clutch cable routing
distributor gear to camshaft compatibility
distributor to ignition system compatiblity
radiator hose routing to water hose routing
radiator fan to shroud fitment
steering wheel size, big easier, small harder, unless you have ps
human butt to seat, the old seats are nostalgic and so is the comfort
How I found it
not much left
The car handles great. It has flowmaster 50 series mufflers which were a bit much with 3.89 gear on the highway. I switched the rear to 3.25 and is a much better daily driver-commuter. The handling impresses people the most. The limiting factor in the handling is the seats. You can't stay planted in the seat with just lap belts on slick vinyl.
Search the following:
opentracker for parts
street or track for performance parts
mustang magazines have articles online
there are other forums for vintage mustangs as well
Use the search function before asking a question. It is very unlikely that you are asking a question which hasn't been answered 50 times on the internet. You can search through google or each forums search button.
Join a local club. The only bad car people I have ever met were dodge people, and that was only a couple of them.